Rocket with internal restriction



Aug. 16, 1966 E. c. WILKERSON ROCKET WITH lliTERNAL RESTRICTION Filed March 28, 1963 FIG. 2

m TM NH W C Y M M E ATTORNEYJ:

rates This invention relates to improvements in rocket propulsion systems and in particular to a rocket having plural thrust levels and an improved thrust-time curve.

It is a particular object of the present invention to provide in a pressurized propellant rocket having a single thrust outlet nozzle at least dual thrust levels, one for accelerating flight and one for sustaining flight.

These and other objects and advantages are provided by a reaction propelled device comprising a container adapted to receive a pressurized expansible propulsion medium, an outlet nozzle at one end of the container communicating with the interior thereof, a partition member mounted inter-iorly of the container between the other end of the container and the outlet nozzle, thereby dividing the container into first and second chambers, and an opening through the partition for the dew of a pressurized expansible propulsion medium between the first and second chambers.

The invention will be more fully described with reference to the illustrated embodiments of the invention wherein:

FIG. 1 is a vertical sectional view through a reaction propelled rocket embodying the principles of the present invention;

FIG. 2 is an enlarged fragmentary sectional view of the rearward end of the device illustrated in FIG. 1 in position in a launching structure; and

FIG. 3 is a fragmentary sectional view through a modified form of partition member for a rocket of the type illustrated in FIGS. -1 and 2.

Referring to the drawings, generally designates a reaction propelled rocket having a tail section 12, a main body portion 1 4, and a nose portion 16.

The tail sect-ion 12 includes an outlet nozzle 18, the rearward end of which communicates with the ambient atmosphere While the inner end communicates with the main body portion 14 of the rocket. The tail or rear- W-ard section 12 may include a stabilizing fin assembly generally designated 20.

The body portion 14 comprises an elongated container having a head portion 22 and a transverse partition 24 which divides the container into a first chamber A and a second chamber B. The partition 24 is provided with at least one opening 26 which provides for communication between chambers A and B.

The nose portion 16 of the rocket is illustrated as containing an explosive composition 28 and as having a detonator 30 at its forward end. It will be appreciated by those skilled in the art that the nose portion of the rocket may contain various types of instrumentation depending upon the mission of the rocket; e.g., radio transmitting and/or recording apparatus associated with temperature, barometric pressure, and humidity sensing means and means for obtaining samples of the air and/ or for releasing smoke or chaff, etc.

The rocket is designed for use with non-burning propellants maintainable under pressure within the propellant composition storage chambers A and B of the rocket and preferably propellant compositions consisting of low temperature boiling, liquefiable normally gaseous materials; gases dissolved in a liquid or mixtures of liquids, or such gases dissolved in a solution of a solid or solids in a liquid or liquids.

Suitable propellant compositions for the rocket may dfihhldd Patented August 16, 1966 comprise, for example, ammonia, Freon, sulphur dioxide, methylchlor-ide, propane, butane; solutions of gases and liquids, such as, carbon dioxide in water, dimethyl ether in Water, difiuoroethane in alcohol, and the like.

While the above-listed propellants and others may be satisfactorily employed in the rocket of the invention, the preferred propellant composition consists of carbon dioxide and acetone. The acetone-carbon dioxide propellant combination has been found to be particularly advantageous as carbon dioxide and acetone are relatively inexpensive, readily available, relatively non-toxic, non-corrosive and the pressure in a cylinder of liquid carbon dioxide is adequate for charging the rocket.

Carbon dioxide is very soluble in acetone and about equal parts by weight of acetone and carbon dioxide under a pressure of from about 500 psi. to about 800 psi. depending upon temperature have been found to provide very satisfactory results as more fully disclosed in United States patent application Serial No. 164,672 filed January 8, 1962 for Rocket, Vernon M. Barnes, Jr., et al., now Patent No. 3,139,794.

The propellant compositions may be placed in the chambers A and B through the outlet nozzle 18 and the outlet nozzle may be provided with a releasable nozzle plug as disclosed in said application Serial No. 164,672 or the outlet nozzle tmay be constructed with a rupturable sealing diaphragm 30 adjacent the constriction in the outlet nozzle 18 in which case the propellant composition is placed within the chambers A and B through a filler valve designated 3-2 in the head portion 22 of the body portion 14 of the rocket. A suitable access opening (not shown in the drawings) is provided in the skin of the rocket.

Where the rocket is provided with a rupturable diaphragm 30, which may be scored as at 3 1 for easy rupture, the rocket is launched by rupturing the diaphragm. Sui-table rupturing means for the diaphragm are illustrated in FIG. 2 wherein the rocket is mounted in a launching tube 34 with the rearward end of the rocket resting against a spider 36 maintained at the lower generally closed end 38 of the launching tube.

The spider 36 centrally supports a tubular member 40 through which a piercing tube 42 reciprocates. The piercing tube 42 is provided with a cutter head 44 at its extended end the piercing tube 42 and its cutter head 44 are urged toward the discharge end of the launching tube 34 by a helical spring 46. One end 48 of the helical spring 46 bears against the spider element 36 while the upper end 50 engages a pin 52 which passes through a bore in the piercing tube 42. In FIG. 2, the diaphragm piercing mechanism is shown in the cooked position and is maintained in the cocked position by a latch pin 54 which is slidably received in a pin guide member 56 carried by the spider 36. One end of the pin is received in a bore 58 adjacent the lower end of the piercing tube 4 2 and the opposite end is secured as at 69 to a flexible firing cable 62. The assembly also includes a safety pin 64 which passes through the guide member 5 6 and the latch pin 54.

Also, as illustrated in the drawings, a flexible band 65 may be provided adjacent the upper end of the piercing tube 42. The band 6 5 aids in centering the piercing tube in the outlet nozzle and guides the piercing tube into piercing relationship with the diaphragm.

To launch the rocket system illustrated in FIG. 2, with the body portion 14 of the rocket precharged with a compressed expansible propellant composition and inserted in the launching tube 34 as illustrated in FIG. 2, the safety pin 64 is withdrawn from its illustrated safety position and the firing cable 62 is pulled to remove the latch pin 54 from engagement with the piercing tube 42 whereby the helical spring 46 urges the cutter head 44 into rupturing engagement with the sealing diaphragm 30. As soon as the diaphragm 30 is ruptured, the compressed propellant composition within the body of the rocket expands through the nozzle 18 thrusting the rocket from the launching tube 34 and into flight.

Ideally, in launchings of the rocket, it is desirable to provide a high thrust during the initial portion of the powered flight and a reduced thrust during the remaining portion of the powered flight to optimize the rockets performance. Variations in the thrust pattern, without varying the outlet nozzle configuration, may be accomplished through the proper selection of the orificed partition 24 illustrated in FIG. 1 of the drawings and by properly positioning the partition within the container to provide the desired ratio of the times of high thrust for acceleration and of the lower sustaining thrust.

In FIG. 1 of the drawings, the partition member 24 is illustrated as being positioned in full lines to provide a chamber A having a volume of about one-third the total volume of the fuel storage container and in broken lines at various other positions. Further, in the illustrated form of the invention, a single orifice is provided in the partition 24 having an effective area larger than the area of the constriction in the outlet nozzle 18. The orifice 26 in the partition 24 may be smaller, the same, or larger than the size of the opening in the outlet nozzle. The mass flow of liquid or vapor contained in the body portion of the rocket, through the opening in the partition 24 would always be less than the flow through the outlet nozzle 18 if there is no substantial difference in area of these openings. For substantially any usable propellant chamber pressure the pressure differential across the nozzle would be greater than across the opening in the partition. Thus, openings smaller, equal to, or somewhat larger in area than the opening in the nozzle throat would be effective for extending the time of discharge of the propellant from the propellant storage chamber in the body portion 14 of the rocket.

The position of the partition 24 in the fuel storage compartment and the number and the size of the openings therein, and the size of the throat in the nozzle would be optimized depending on rocket size and weight and the requirements of the mission.

As discussed hereinbefore, the partition member may have more than one opening therein and the area of the opening or openings may be smaller, larger or the same as the area of the constriction in the outlet nozzle. One modified form of partition member is illustrated in FIG. 3 wherein the partition member is designated with the reference character 24. The partition member 24', which is adapted to 'be mounted in the rocket illustrated in FIGS. 1 and 2 in place of partition member 24, is providcd with a plurality of openings or orifices 26 and the total area of the plurality of orifices is less than the area of the constriction in the outlet nozzle 18 of the rocket shown in FIGS. 1 and 2.

Example A rocket having an overall length of about 40 inches and a diameter of 2 /2 inches was provided with a nose portion 16 7 /2 inches long and adapted to receive approximately 1 pound of high explosive. The fuel containing compartment was 20 inches long and was charged with 1.4 pounds of carbon dioxide and 1.4 pounds of acetone at 800 psi.

The area of the throat of the outlet nozzle was about .077 square inch and the partition member was provided with 13 orifices having a total of .050 square inch. The partition was positioned to provide substantially A1. of the volume of the propellant compartment in the lower chamber A. With this arrangement, an increase in thrust duration greater than 20% was provided over an identical rocket without the partition member.

From the foregoing detailed description of the improved reaction propelled device, it will be seen that the aims and objects of the invention have been fully accomplished. While particular embodiments and methods of operation of the present invention have been disclosed for the purposes of illustration, various modifications may be made in the form of the rocket Without departing from the scope of the invention as defined in the appended claims. For example, the pressurized fuel containing compartment may be divided into a plurality of cham'bers by partition members each having one or more orifices which may differ in area whereby the rocket may be provided with a very high lanuching thrust, an intermediate accelerating thrust and a relatively low flight sustaining thrust thereby optimizing the performance of the rocket for a particular mission.

I claim:

1. A reaction propelled device comprising a container, a pressurized expansible propelling medium in said container, an outlet nozzle at one end of the container communicating with the interior thereof, closure means for said nozzle, at least one partition member mounted inwhereby, when said closure means is opened, the initial thrust level due to said propelling medium escaping through the nozzle will be high due to high equilibrium pressure in all said chambers, and whereby the thrust level will decrease as the pressure in the chamber in direct communication With the nozzle falls to a reduced level determined by the restricted flow rate through said orifice, said restricted rate also serving to increase duration of thrust.

2. The reaction propelled device defined in claim 1 wherein the closure means for the nozzle comprises a rupturable diaphragm.

3. The reaction propelled device defined in claim 1 wherein the area of the orifice in at least one partition member is larger than the area of the opening through the outlet nozzle.

4. The reaction propelled device as defined in claim 1 wherein the effective area of the orifice in at least one of the partition members is less than the effective area of the opening through the outlet nozzle.

References Cited by the Examiner UNITED STATES PATENTS 263,407 8/1882 Hicks 35.5 X 2,856,851 10/1958 Thomas 6035.6 2,876,620 3/1959 Weinland 6035.6 3,031,842 5/1962 Ledwith 10249 X 3,034,293 5/1962 Ferris et al. 6035.6 3,066,484 12/1962 Buchanan et al 6035.6 3,070,014 12/1962 Gose 6035.6

MARK NEWMAN, Primary Examiner.

SAMUEL FEINBERG, Examiner.

G. L. PETERSON, R. D. BLAKESLEE,

Assistant Examiners. 

1. A REACTION PROPELLED DEVICE COMPRISING A CONTAINER, A PRESSURIZED EXPANSIBLE PROPELLING MEDIUM IN SAID CONTAINER, AN OUTLET NOZZLE AT ONE END OF THE CONTAINER COMMUNICATING WITH THE INTERIOR THEREOF, CLOSURE MEANS FOR SAID NOZZLE, AT LEAST ONE PARTITION MEMBER MOUNTED INTERIORLY OF THE CONTAINER BETWEEN THE OUTLET NOZZLE AND THE OTHER END OF THE CONTAINER DIVIDING THE CONTAINER INTO AT LEAST TWO CHAMBERS FOR THE EXPANSIBLE PROPELLING MEDIUM, AND AT LEAST ONE ORIFICE THROUGH EACH OF THE PARTTION MEMBERS RESTRICTING THE FLOW OF SAID PRESSURIZED EXPANSIBLE PROPELLING MEDIUM BETWEEN SAID CHAMBERS WHEREBY, WHEN SAID CLOSURE MEANS IS OPENED, THE INITIAL THRUST LEVEL DUE TO SAID PROPELLING MEDIUM ESCAPING THROUGH THE NOZZLE WILL BE HIGH DUE TO HIGH EQUILIBRIUM PRESSURE IN ALL SAID CHAMBERS, AND WHEREBY THE THRUST LEVEL WILL DECREASE AS THE PRESSURE IN THE CHAMBER IN DIRECT COMMUNICATION WITH THE NOZZLE FALLS TO A REDUCED LEVEL DETERMINED BY THE RESTRICTED FLOW RATE THROUGH SAID ORIFICE, SAID RESTRICTED RATE ALSO SERVING TO INCREASE DURATION OF THRUST. 